The use of metallic iron floor toppings has been heretofore known. The benefits that have been derived from such toppings and the problems that have occured since the first floor toppings were put in place in the early 1900's are known. An early patent for a metallic shake is U.S. Pat. No. 1,113,112, of S. W. Flesheim. The patent describes the use of metallic iron borings which are combined with Portland cement in various percentages depending upon the type of metallic floor topping desired. Throughout the early history, this was believed to be the only metallic iron boring mix used in the application of increased wear resistance on industrial floors. It became known as time went on and more floors of this type were installed, that there were some inherent problems with the use of metallic iron borings. For example, the floor gave a very dark color and was extremely poor in light reflectivity. When the floor came in contact with water and/or calcium chloride ions, whether it had been incorporated into the concrete mix to accelerate setting times, or from being deposited on the surface from vehicles that had been out on the streets during the winter time when chloride had been put on the roads to assist in deicing, extreme oxidation of the metallic iron borings became evident. Disruption of the surface due to the expansion caused by the oxidation of metallic particles caused disintegration, staining, tracking of oxidized material and a generally unsightly floor.
Various coatings over the years have been applied over the freshly placed metallic iron boring shakes and toppings such as chlorinated rubber curing and sealing compound and other types of sealing materials. After traffic in heavy-duty areas ran over the floor for a given period of time, the thin coating wore off and the metallic iron particles were once again exposed to the atmosphere. It became apparent that there were limitations on where metallic iron toppings could be installed. They generally had to be installed in dry warehouses and dry factory areas. By placing a metallic iron topping outside, oxidation would occur almost immediately on the surface due to climatic conditions. In areas of freezers and food processing plants which have to maintain high cleanliness standards, large amounts of cleaning agents and water are always present. Extreme oxidation and unsightliness occured quickly after the installation of these floors.
Over the years, various chemicals have been incorporated with metallic iron toppings such as shown in U.S. Pat. No. 3,668,150. U.S. Pat. No. 3,668,150 shows the incorporation of sodium nitrite in the mix with metallic iron to help prevent the oxidation of the iron particles. Though it is true that it does help prevent initial oxidation, as soon as the particles are exposed to water, chlorides and air oxidation occurs as rapidly as in a mix without the sodium nitrite.
U.S. Pat. No. 1,348,099 discloses the use of copper plated iron borings or turnings as a surface finish in concrete floors. The plating of iron particles, however, for the purpose of retarding oxidation is not only expensive but is of limited effectiveness. In time, the plating erodes causing oxidation of the particles to commence.
In U.S. Pat. No. 1,056,069, silicon carbide material (i.e., Carborundum) is incorporated in concrete to produce a wear resistant floor surface.
U.S. Pat. No. 1,802,667 discloses a Portland cement composition which includes aluminum and ferrosilicon. The ferrosilicon is added for the purpose of allegedly reacting with calcium hydroxide. Presumably by setting up a reaction with the calcium hydroxide, there is created an insoluble compound which retards disintegration of the concrete in the presence of salt carrying percolating water.
Another aspect to improving floor compositions has come about due to the energy conservation that companies are trying to introduce. That is the ability to put in an abrasion resistant floor in factories and work areas and also maintain some light reflectivity values. The original metallic iron topping was extremely dark and various pigments have been added to lighten the floor surfaces. White Portland cement has been used for some years incorporating titanium dioxide and other lightening agents. The problem still exists that as soon as the dark metallic iron boring surface is exposed through wear, water or chlorides, oxidation occurs rapidly.